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426 Wisconsin Academy of Sciences, Arts, and Letters. 
before mentioned. But when we assume that the Chironomid 
species in question are ammophilous and that by settling on 
the sandy shore they merely expanded the horizon of their habi¬ 
tat, the apparent discrepancy will be understood. 
E. The Bars .—Physiographically bars are continuous with 
the shore. In all respects the various bars of the lake show 
the same physical and physiological characteristics as the stony 
and sandy shores; to all intent they are precisely like these in 
their faunal makeup. Hence they will not be treated as sep¬ 
arate ecological entities, but are to be included in the stony 
shore association. 
2. The Kachion (breaker line). 
Physiographically, the rachion is frequently a separate entity, 
while at times it is a unit with the shore line. This is depend¬ 
ent primarily on the slope of the shore. On steeper shores the 
breaker line is continuous with the shore line, rocky, stony, or 
sandy, as the case may be. In shallower areas it is detached 
from the shore, often several hundred meters from the latter; 
here, too, it may be frequently divided into two lines,—an 
outer” and an ‘dnner bar.” Physically, its make-up again 
depends on its location. If continuous with the shore line 
proper, it can be recognized by its makeup of rocks, gravel, 
and sand,—the rocks in the middle, while the smaller ingredi¬ 
ents will be piled on either side. In places where a rocky 
shore extends downward a number of meters, the breaker line 
is usually recognized by the absence of algal growth at the line 
and by the gravel heaped on either side. Where the breaker 
line is detached from the shore, it is easily marked as a stony 
area some 5-8 meters in width running parallel to the shore. 
Its middle section is invariably composed of larger stones, 
while gravel and sand lie on either side. In the larger shal¬ 
lows it is followed some meters closer to the shore by a second¬ 
ary breaker line. 
Physiologically, the rachion, or breaker line, marks the place 
where wave action and undertow cause the greatest turmoil; it 
is the point of extremes in lake conditions. 
Faunistieally, it is comparable to stony shores. Its fauna is 
largely the same, except that Polyeentropus and various 
Chironomid species are extremely abundant in it. We must dis- 
